1. Field of the Invention
This invention relates to a stabilized organic peroxide composition and process for making the same which comprises an organic peroxide and a stabilizing compound which retards the rate of decomposition of the peroxide compound.
2. Description of the Related Art
Organic peroxides are utilized in a wide variety of chemical applications, including their use as free-radical initiators in the polymerization or copolymerization of ethylenically unsaturated monomers. Organic peroxides are by their very nature unstable and tend to decompose when exposed to elevated temperature or extended storage conditions resulting in liberation of heat and oxygen, putting them at greatly increased risk for fire and/or explosion. As a result, many peroxides must be refrigerated. A variety of stabilizers have been used to stabilize organic peroxides such as peroxydicarbonates. However, there continues to be a need for new and effective stabilizer compositions which can mitigate the hazardous nature of organic peroxides while not interfering with their subsequent use as free-radical initiators.
The use of stabilizers for organic peroxides has been widely known in the art. For example, U.S. Pat. No. 4,515,929 discloses aqueous dispersions of organic peroxides including peroxydicarbonates, which are stabilized against decomposition by the addition of diphenyl peroxydicarbonate or di(alkyl substituted) phenyl peroxydicarbonates.
U.S. Pat. No. 4,552,682 discloses the use of phenolic antioxidants to retard the rate of degradation of aqueous organic peroxide dispersions. The use of phenolic antioxidants is undesirable because they result in discoloration.
U.S. Pat. No. 5,155,192 discloses the use of organic hydroperoxides, e.g., tert-butyl hydroperoxide, to retard the rate of decomposition of peroxydicarbonates.
U.S. Pat. Nos. 5,541,151 and 5,548,046 report thermally stabilized compositions of a dialkyl peroxydicarbonate and a stabilizing amount of an ethylenically unsaturated nitrile or ethylenically unsaturated acetylenic compound.
U.S. Pat. No. 5,654,463 reports the use of alpha-hydroxyalkyl peroxides as stabilizing agents for peroxides, such as peroxydicarbonates.
U.S. Pat. No. 5,654,464 reports the use of cyclic alpha-diketone compounds to retard the rate of decomposition of organic peroxides, such as peroxydicarbonates.
U.S. Pat. No. 5,719,304 reports the use of phosphomolybdic acid as a stabilizing agent for organic peroxides.
U.S. Pat. No. 5,714,626 reports the use of beta-dicarbonyl compounds as stabilizing agents for organic peroxides.
U.S. Pat. No. 5,892,090 reports the use of oximes as materials which will retard the rate of decomposition of organic peroxides.
U.S. Pat. No. 6,399,728 and U.S. Patent Application No. 2002/0177678 report the use of dialkyl maleate and fumarate esters as stabilizing agents for dialkyl peroxydicarbonates. The esters of this invention are incorporated into the polymer during the polymerization process.
U.S. Patent Application No. 2002/0091214 reports the use of reactive phlegmatizers as diluents for organic peroxides. These mixtures are reported to be safe to produce, handle and transport. The phlegmatizers reported include (cyclic) olefins, aldehydes, ketones, alcohols, and mixtures thereof. In particular, olefins such as 1-octene and alpha-methyl styrene are claimed. Many different classes of peroxides are included within the scope of this application. The mixtures of this invention are useful for the polymerization of ethylene, styrene, vinyl chloride, etc. The reactive phlegmatizers are said to be incorporated into the polymer formed during the polymerization process, although no experimental data is given to support this claim.
World Patent Application WO 02/051879 reports reactive diluents for peroxides. In particular, vinyl ethers, such as hydroxybutyl vinyl ether, or a resinous compound containing vinyl ether groups, are reported. The peroxides mentioned in this application include methyl ethyl ketone peroxide, benzoyl peroxide, acetylacetone peroxide and cyclohexanone peroxide. The mixtures are used to cure polyester resins.
World Patent Application WO 03/002527 reports the stabilization of peroxydicarbonates using alpha-unsaturated ketones.
The Journal of The American Chemical Society, Volume 72 pages 1254 to 1263 (1950) discloses the use of, for example, ethyl acetoacetate, iodine, trinitrobenzene, acetanilide, nitromethane, phenol, hydrogen peroxide, and tetralin to retard the rate of decomposition of diisopropyl peroxydicarbonate.